1) A slot can only have one attachment. A region attachment and a bounding box attachment are both attachments. You should have two slots, one with the region and one with the bounding box.

2) A bounding box attachment can be in a skin just like a region attachment. Currently you can only create a bounding box on a slot, but after creation you can drag it (or set parent) to a skin placeholder (make sure the skin placeholder is empty). I'll add a way to create a bounding box directly on a skin placeholder, like it is done for slots.

I have 2 points ....

1) even when I add a bounding box to a slot, I get the icon for the adding bounding box points, but clicking doesn't add any points (OSX)
2) can there be a rudimentary system for just producing a box ? chances of me lining up the points to actually be a box are pretty slim ... (although you are bound to tell me holding shift freezes an axis aren't you )

1) Are bounding boxes visible? See the eye column in the main toolbar under Options to the right of Bounds>
2) There are no primitive shapes yet. However, there is likely no difference between an exact rectangle and your best approximation.

1) ahh, yes that did it. my bad. you should see the bounding box shape that just appeared lol !
2) You are right of course, when I think about it. My usage will not be rotating them anyway, so I will only use the 2 corners

one small thing. If I have a bounding box, and then accidentally click the set points again, without warning, I lose the entire bounding box already there ? You might want to pop up a dialog ..

For now just undo if you smoke your bounding box on accident. I've improved the button so if you click it and then exit the set point mode without creating points, then it reverts to the old points.